JPH08200738A - Air conditioner - Google Patents

Abstract

PURPOSE: To omit about 25% of the maximum value energy effect by conserving cooling or heating energy to be consumed, and utilizing energy reciprocal to the cooling or heating without using external substitute energy in an air conditioner for a clean room for manufacturing semiconductor. CONSTITUTION: A route duct 15 branched from a return air route 7 to an air conditioner 13 is provided in an external air conditioner 2 in addition to a conventional external air introducing route 1 in the air conditioning particularly in an intermediate season and winter, and hence the energy for the external air conditioning is remarkably reduced by cancelling by the mixing effect of the introduced atmosphere and the return air at the inlet of the conditioner 2. The part of the return air including the internal heating load is branched to the conditioner 2 to reduce the absolute amount for conditioning by the conditioner 3. The conditioning energy is reduced proportionally thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly to an air conditioner for producing and maintaining an ultra-clean air environment in a clean room used for VLSI production.

[0002]

2. Description of the Related Art Energy-saving technologies in conventional air conditioners are roughly classified into two: first, a labor-saving technology by improving operating efficiency, and second, a labor-saving technology by alternative energy. Referring to FIG. 4, which shows a schematic diagram of an air conditioner incorporating this type of energy-saving technology, this device includes an outside air intake path 1 and an outside air conditioner 2 for adjusting the introduced outside air to a set temperature and humidity. , An air conditioner 3 that harmonizes the mixed air of the conditioned outside air and the return air and sends the air to the clean room again, a fan 4 that circulates clean air to maintain cleanliness, and captures dust in the conditioned air. Hep for ensuring cleanliness
The filter 5 includes a filter 5, a clean room 29 partitioned by the filter 5, a supply chamber 30, other cooling means, and piping.

Here, the outside air conditioner 2 is provided with a heater (steam heating coil) 21, a steam spraying humidifying pipe 34, a cooler (cooling coil) 22, and a blower fan 23, and further has an outside air inlet and an outside air. And a lead-out port to the duct 6. The outside air intake path 1 is provided with a cold gas heat exchanger 24 and an air volume adjusting manual damper 25. Cold gas heat exchanger 24
A nitrogen tank 10 is connected to the. Refrigerant is sent to the cooler 22 from the well 9, the refrigerator 8, or the cooling tower 11 using the water supply pump 26, respectively.

The air conditioner 3 has an outside air inlet from the outside air duct 6, a return air inlet from the return duct 7, and an outlet to the supply chamber 30, each of which has a cooler 27 and a steam spray type inside. Humidification pipe 32 and blower fan 28
With. The well 9, the refrigerator 8 and the cooling tower 11 are prepared as cooling sources for the cooler 27 in the air conditioner 3.

The circulation fan 4 is necessary for sending the air in the return chamber 31 into the supply chamber 30. The clean room 29 is a work area and is required to have a high degree of cleanliness. This clean room 2
The upper surface of 9 is in contact with the supply chamber 30 through the low pressure loss Hepa filter 5, the side is in contact with the service area 35 in which various equipments are installed, and the pressure sensor 14 is interposed. The lower surface or floor surface opens into the return chamber 31.

The return chamber 31 has outlets to the return duct 7 and outlets to the fan 4, and a pipe connecting the equipment in the service area 35 to the cooling tower 20 and the cold water heat exchanger 12. pass. The service area 35 is provided with a fan 33 for sending out to the outside air, and an inverter 13 for controlling the sending amount of the fan 33 is also provided.

The clean room 29 in which the worker works is
In order to prevent the inflow of dust from the service area 35 where the equipment is installed, a slight pressure difference (about 2 m
mHg) must be maintained. In order to maintain such a room-to-room differential pressure, the pressure sensor 14 detects it and sends a signal to the fan 23 of the outside air conditioner 2 having an inverter control function to control the rotation speed of this fan 23.

The inverter 13 receives a signal that detects the amount of exhaust required by the equipment, and receives the exhaust fan 3 for external exhaust.
It is a device for controlling the number of revolutions of 3 and suppressing unnecessary power consumption.

The Hepa filter 5 is provided between the supply chamber 30 and the clean room 29. As another filter, a dust and medium performance pre-filter is installed at the outside air inlet of the outside air conditioner 2 to suck in air. The coarse dust is collected, and a high-performance prefilter is installed in the air conditioner 3 in an effort to maintain cleanliness, but neither is shown.

The low pressure loss Hepa filter is Hep.
a (High efficiency particula
te air) filter, which is usually called an ultra-high performance filter, is a kind of filtration type filter and can collect submicron particles with extremely high performance. The performance of this filter is 99.000 for particles with a collection rate of 0.3 μm.
92% or more and the initial pressure loss at rated air flow is 2
It is specified to be 5.4 mmAg or less.

The cold / heat source, which will be described later, uses cold water as a cold source for temperature control (air dehumidification, cooling) in an air conditioning system. Centrifugal refrigerators, absorption refrigerators, and the like are typical cold water producing machines.

In the air conditioner of FIG. 3, assuming that the amount of clean air in the clean room 29 is 100%, the return chamber 31 opened on the floor surface is connected to the return duct 7 by three.
7% and 63% to fan 4. To the air conditioner 3, 37% from the return duct 7 and 8% from the outside air duct 6 are introduced, and a total of 45% is introduced to the supply chamber 30 by the fan 28. 108% together with 63% from the fan 4 is introduced into the supply chamber 30, 8% of which is exhausted to the outside air by the fan 33.
Therefore, the amount of outside air introduced into the outside air conditioner 2 is 8%.

Many semiconductor manufacturing apparatuses based on a high temperature process are accompanied by a large amount of heat generation, and are a large heat load source for a clean room. However, the manufacturing work environment is severely required to have a fluctuation range of temperature ± 2 ° C. and humidity ± 10% RH. Although the automatic temperature / humidity control system in FIG. 3 is not shown, it has a negative feedback control configuration as described below.

The indoor temperature detector in the clean room 29 inputs the temperature in the clean room to the outside air room temperature difference indicating controller, operates the proportional control motor valve in accordance with the temperature difference, and steam is introduced into the outside air conditioner 2. The amount introduced into the heater 21 is adjusted.

The indoor temperature / humidity detector in the clean room 29 sends temperature information to the indoor temperature indicating controller, operates the proportional control motor valve, and introduces cold water into the cooler 27 in the air conditioner 3. In addition to adjusting the amount, the humidity information is sent to the indoor temperature / humidity indicator controller, and the proportional control motor valve is operated to adjust the amount of steam introduced into the steam spray humidifier pipe 32.

The outside air temperature detector in the outside air conditioner 2 sends outside air temperature information to the outside air temperature indicating controller, and based on this, the amount of cold water introduced into the cooler 22 is adjusted by a motor valve. The dew-point humidity detector provided in the outside air duct 6 sends the humidity information to the dew-point humidity indicating controller, and adjusts the amount of steam introduced into the humidifying pipe 34 in the outside air conditioner 2 with a motor valve.

The above five automatic control systems are provided.
The factors of variation include the temperature and humidity of the outside air, the lighting and power in the clean room 29, the heat generated by people in the room, and the heat generated by the manufacturing equipment in the service area 32.

In the conventional energy-saving technology applied to the air conditioner configured as described above, the mainstream is labor-saving by substituting the cold heat source. Cold water produced by the refrigerator 8 is used as a normal cooling source for the outside air conditioner 2 and the air conditioner 3, but in the summer, as an alternative, a natural cold heat source such as water in the well 9 or nitrogen (N ₂ ). Evaporative cooling such as latent heat of vaporization from the tank 10 is utilized. Both of them supplement energy for cooling and dehumidifying the outside air.

Further, since the outside air in the winter is in a low temperature dry state, the cooling water cooled in the cooling tower 11 is used as an alternative cold / hot heat source for the air conditioner 3 which needs to be cooled all year round, thereby saving labor. .

Energy saving technologies throughout the year are utilization of waste heat and high efficiency. This is the adoption of high-efficiency rotary equipment used in this device, the adoption of low-pressure loss Hepa filter, and the like, and the air volume control and the number control of the inverter 13 and the pressure sensor 14. Further, utilizing the exhaust heat of the cooling water for warming the pure water by the cold water heat exchanger 12 is an energy saving technique in the conventional air conditioner.

[0021] As other prior art which is considered to be related to this, Japanese Patent Laid-Open No. 63-298513, which describes a cooling device for electronic equipment used in a computer, and an air-conditioning system in a portable communication facility accommodating range are described. Japanese Patent Laid-Open No. 64-782
No. 3, for example, is strongly suggested, but it is not a system for managing temperature, humidity and cleanliness, and no actual configuration regarding this point is shown.

[0022]

In the above-described conventional air conditioner, since only the steam introduced into the heater 21 is used as the heat source of the outside air conditioner 2 which performs the outside air treatment, the processing energy cannot be reduced. There is.

Further, since the return air having a temperature as high as 37% is input into the air conditioner 3, a large cooling capacity of the cooler 27 is required.

As described above, there is a drawback in that the balance of the air conditioning system is poor and the running cost cannot be minimized. From the above, we recognized the necessity of re-evaluation for air conditioning duct routing and outside air introduction amount adjustment.

Further, conventionally, the following problems are pointed out.

(A) Since it is an alternative to a natural cold heat source or the like, it lacks quality stability and it is difficult to secure and maintain a stable amount.

(A) The utilization rate of external energy is high, and equipment for that purpose is required.

(C) The biggest problem is that the maximum energy saving effect rate is about 20% at most.

(D) Temperature, humidity and air cleanliness cannot be controlled with high precision and high grade.

In the present invention, in order to solve such problems, unlike the conventional energy-saving technology which focuses on the replacement of the cold heat source, the structure of the air conditioner itself is reviewed to save labor. Focusing on such issues, the following issues are raised. (1) Accuracy of temperature ± 2 ° C and humidity ± 10% RH should be obtained. (2) To reduce the dependency of external energy and improve the reliability of air conditioning. (3) Able to secure and maintain sufficient quantity and quality. (4) To increase the maximum energy saving effect rate. (5) The device scale should be small. (6) No major design changes to conventional equipment. (7) The air conditioner itself should be omitted. (8) Reduce air conditioning running costs. (9) To reduce the heat source energy required for outside air treatment, especially during the winter. (10) To reduce the cold / heat source required for dew point cooling in the air conditioner. (11) To improve the overall balance of the air conditioning system,
Do not increase local processing power.

[0031]

SUMMARY OF THE INVENTION The structure of the present invention includes an outside air conditioner for adjusting the outside air that changes with time, and an air for adjusting the outside air conditioned by the outside air conditioner and the internal heat generation in the clean room. In an air conditioner including a conditioner and a fan that circulates clean air in the clean room, a path duct for returning air from the clean room to the outside air conditioner is provided.

In particular, the outside air conditioner has a function of mixing and adjusting the outside air and the return air.
Further, in particular, the path duct is also characterized in that the return air from the clean room is a branch duct in which the outside air conditioner and the air conditioner are distributed, and more particularly from the outside air conditioner to the air conditioner. It is also characterized in that the path duct is set so that the amount of outside air introduced and the amount of return air introduced from the clean room to the air conditioner are substantially equal.

[0033]

FIG. 1 shows an air conditioner according to an embodiment of the present invention.
Referring to the schematic diagram of 1., one of the main characteristics of this embodiment is that there is a path duct 15 that branches from the return duct 7 and opens to the outside air conditioner 2.

The automatic control system and the like described in FIG. 4 exist, and the refrigerator 8 also exists to supply the energy required for dehumidification / cooling as a heat source of the outside air conditioner and the air conditioner 3. Further, the humidified and heated steam is supplied from a boiler installed separately, but neither is shown in FIG. 1 and is omitted.

The nitrogen tank 10, cold gas heat exchanger 24, well 9, cooling towers 11 and 20, cold water heat exchanger 12 shown in FIG.
The water supply pump 26, the pressure sensor 14, the inverter 13 and the like may be present in FIG. 1, but are not necessarily essential.

However, in this embodiment, the outside air intake passage 1, the outside air conditioner 2 including the heater 16, the cooler 17, the fan 33, and the humidification pipe 34, the cooler 18, and the humidification pipe 3 are included.
2, the air conditioner 3 including the fan 28, the fan 4, the filter 5, the outside air duct 6, the return duct 7 and the like are common to those of the conventional FIG.

In this embodiment, since the route duct 15 branched from the return duct 7 is guided to the outside air conditioner 2, 22% of the 37% air amount in the return duct 7 is in the air conditioner 3. Although it is sent through the return duct 7 ′, the remaining 15% is sent to the outside air conditioner 2. Outside air 8% and path duct 15% are introduced into the outside air conditioner 2, and these are mixed and sent to the inside of the air conditioner 3 as 23%. The other air amounts are omitted since they are common to the description in FIG.

Referring to the moist air diagram of FIG. 2 showing the operating functions of FIG. 1, the horizontal axis is the scale of the dry-bulb temperature from −5 ° C. to + 45 ° C., and the vertical axis is from 0.000 to 0.034. It is a scale of absolute humidity [kg / kg ']. The boundary curve between the supersaturated air region on the left side (state including water droplets) and the unsaturated air region is defined as a saturated air line 40. Absolute humidity is the amount of water vapor relative to the amount of dry air. Here, the point RA on the T point indicates the air containing a predetermined temperature and humidity in the return chamber 31, the black circle point on the S point indicates the air in the clean room 29, and the point S on the R point.
A indicates air supply from the fan 28 in the air conditioner 3, and point (c) is that the air in the outside air duct 6 and the air in the return duct 7'are mixed and settled.

The outside air in the outside air intake passage 1 (shown by a double circle) is mixed with the air in the passage duct 15, that is, the return air in the return chamber 31 at the point T, and the arrows (1), (1
Go to the direction of 5) and settle on point (a) indicated by point R. Next, it is humidified by the humidifying pipe 34 of the outside air conditioner 2 and reaches the point (b). This is the air in the outside air duct 6. The air in the outside air duct 6 and the air in the return duct 7 '(point RA) are mixed in the air conditioner 3 and face in the directions of the arrows (6) and (7') to reach the point (c). Calm down. Next, it is cooled by the cooler 18 and settles at a point (d) facing in the direction of the arrow (18), and this is sent to the supply chamber 30 by the fan 28. In the supply chamber 30, the return air (point RA) and the air from the fan 4 are mixed, and the clean room 29
The atmosphere inside is created. This point corresponds to the black circle above point S.

In the conventional air conditioner of FIG. 4, the outside air is introduced into the outside air conditioner 2 and the broken line arrow (1) in FIG.
Go through 6) and (17) to be harmonized. Clean room 29
Internal heat generated therein is sent to the air conditioner 3 through the return duct (7). Air conditioner 3 entrance (point (c))
Then, cooling is performed by mixing with the harmonious outside air 6,
The remaining heat load passes through the cooler 27 of the cooling coil, is harmonized with the set temperature and humidity (point (d)), and is again sent to the clean room 29. Such conventional harmony of the outside air requires a large amount of energy because it passes through the broken line route of FIG.

Therefore, in this embodiment, the return duct 15
When it is branched from the return air duct 7 and provided at the inlet of the outside air conditioner 2, the same mixing effect as that of the air conditioner 3 occurs in the outside air conditioner 2. In FIG. 2, the solid arrows (1) and (15) cancel each other out, and the energy for harmony is about 70% because the energy for points (a) to (b) is sufficient. . Further, by branching a part of the return air including the internal heat load to the outside air conditioner 2,
Since the amount of harmony in the air conditioner 3 is reduced, energy is saved by about 30%. Therefore, the energy saving rate of total cold energy is about 50%.

Referring to the monthly energy consumption [%] of FIG. 3 showing such an energy saving state, especially in the winter season, 1
In the month and February, there is an effect that energy saving of about 50% (hatched portion) can be achieved.

The air mixing ratio in the above-described embodiment is, in terms of cost, in the outside air conditioner 2, preferably 1 outside air introduction amount and 2 return air amount, and the air conditioner 3
In the above, the return air amount is preferably set to 1 with respect to the external air harmony amount 1, but the present invention is not limited to this, and other different air mixing ratios can be taken.

It is preferable that the return duct 7 is branched into the return duct 7'and the route duct 15 on the way from the viewpoint that a simpler modification work is required. Direct inlet to return chamber 3
You may open in 1.

The temperature / humidity points of points (a) to (d) in FIG. 2 are shown by their common alphabet in FIG.

As described above, according to the present invention, since the amount of heat used for the heating / humidifying process is obtained from the return air, the minimum amount of steam is sufficient, and the reduction of outside air processing energy can be expected. As the amount of return air in the air conditioner 2 is reduced, the cooling energy used for cooling the mixing air is minimized, and the air processing energy in the air conditioner 2 can be reduced.

Further, according to the present invention, in the outside air conditioner 2, the heating and humidifying by the steam energy and the cooling and dehumidifying by the cooling energy are performed in the outside air conditioner 2 in response to the state of the outside air which changes with time. However, since part of the conditioned clean air in the clean room 29 is returned to the outside air conditioner 2, energy is significantly reduced due to the mixing effect, and the amount of harmony also decreases in the air conditioner 3. The energy consumed as a whole is reduced.

[0048]

As described above, according to the present invention, it is possible to save the maximum energy saving effect rate of about 25% by utilizing the energy contradictory to cooling and heating without using external alternative energy. The use of clean air created by the air conditioner itself does not require special equipment, and has the effect of obtaining a device that is stable in quality and quantity and highly reliable. To be achieved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an air conditioner of an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing an operation of one embodiment as a movement of energy on a moist air line.

FIG. 3 is a characteristic diagram showing a transition of annual energy consumption according to an embodiment.

FIG. 4 is a schematic view of an air conditioner according to a conventional energy saving technique.

[Explanation of symbols]

 1 Outside air intake route 2 Outside air conditioner 3 Air conditioner 4, 23, 28, 33 Circulation fan 5 Filter 6 Outside air duct 7, 7'Return duct 8 Refrigerator 9 Well 10 Nitrogen tank 11, 20 Cooling tower 13 Inverter 14 Pressure sensor 15 Path duct 16,21 Heater 17,18,22,27 Cooler 24 Cold gas heat exchanger 25 Manual damper for air flow adjustment 26 Water supply pump 29 Clean room 30 Supra chamber 31 Return chamber 32,34 Steam atomizing humidifier pipe 35 Service area 40 Saturated air

Claims (4)

[Claims] 1. An outside air conditioner for adjusting the outside air that changes with time, an air conditioner for adjusting the outside air conditioned by the outside air conditioner and the internal heat generation in the clean room, and clean air in the clean room. An air conditioner provided with a fan that circulates the air conditioner, wherein a path duct for returning air from the clean room to the outside air conditioner is provided. 2. The air conditioner according to claim 1, wherein the outside air conditioner has a function of mixing and adjusting the outside air and the return air. 3. The air conditioner according to claim 1, wherein the path duct is a branch duct in which the return air from the clean room is distributed between the outside air conditioner and the air conditioner. 4. The path duct is set so that an amount of outside air introduced into the air conditioner from the outside air conditioner and an amount of return air introduced into the air conditioner from the clean room are substantially equal to each other. The air conditioner according to claim 1.